1. Field of the Invention
The present invention is directed to an optoelectronic device including an optoelectronic transducer and a cooling device for accurately controlling the temperature of the optoelectronic transducer.
2. Description of the Related Art
Optoelectronic devices, such as detectors and light sources, are very sensitive to temperature. The response sensitivity or wavelength output for optoelectronic devices can vary even with a slight change in temperature. Hence, accurate signal detection/generation can be achieved only with highly precise control of the temperature of optoelectronic devices.
Non-cooled transistor outline (TO) can optoelectronic device packages do not include electronic cooling modules for temperature control. Instead, TO-can optoelectronic device packages adopt an indirect cooling system by installing a separate cooling unit outside the TO-can package. Accordingly, non-cooled TO-can optoelectronic device packages do not completely contact the surface of the cooling unit. Thus, heat output by the optoelectronic device cannot be properly thermally coupled to the cooling unit. Also, in TO-can optoelectronic device packages, a temperature-sensing probe is indirectly fixed to a heat transmission block. Thus, the probe cannot accurately sense the temperature of the TO-can optoelectronic device packages.
There are many situations in which inaccurate control of the temperature of an optoelectronic device adversely affects performance. For example, to measure the concentration of glucose in human blood, light sources outputting light in a specific wavelength band, including a first wavelength band at which glucose has a high absorption and a second wavelength band at which glucose has a low absorption, is needed. After illumination of a part of a human body with the specific wavelength band, a TO-can optoelectronic device package, typically an infrared (IR) sensor, measures light reflected or transmitted by the part of the human body. The glucose concentration is calculated by statistically analyzing a difference between the amount of light absorbed in the first and second wavelength bands.
However, the absorption spectrum shifts very slightly with a change in the glucose concentration. Accordingly, a change in the absorption spectrum arising from a change in the temperature of the sensor must be less than that arising from a change in the glucose concentration. As a result, the temperature of the sensor must be precisely maintained at a target temperature.
To realize this temperature control, a spectrophotometer for performing such glucose measurement may include a closed housing in which a temperature sensing element is disposed near an IR TO-can sensor. Accordingly, this necessitates an additional closed housing element. Further, in the spectrophotometer, an electronic cooling module is disposed underneath the sensor. As a result, the state of thermal coupling of the electronic cooling module to the TO-can sensor is improved. However, because a sensor probe for monitoring the temperature of the TO-can sensor is disposed directly on the electronic cooling module, e.g., on the same surface on which the TO-can sensor is mounted, the temperature of the TO-can sensor cannot be accurately detected.